DateTime function to convert to time.Time value (close #115)

[mholt]

This change adds a DateTime function as discussed in #115.

[icholy]

@aldas are you ok with this API?

[mholt]

That's a valid point; I guess it's more conventional to have optional arguments last. Refactored and pushed :)

[icholy]

They sorry for the delay, I haven't had access to my computer for the past couple days.

should referenceYear be first parameter as it is optional and d and t are "main" things here we are combining but they come after "optional" parameter.

The referenceYear parameter isn't optional though, it must be explicitly passed every time. If Go did support optional parameters then putting it last would make sense because you'd be able to omit it at the call site.

nmea.DateTime(d, t)

I put the referenceYear first because it's the most significant unit. It's roughly modeled after time.Date signature which follows the same left to right pattern.

func Date(year int, month Month, day, hour, min, sec, nsec int, loc *Location) Time

I won't die on this hill though. @mholt care to be the tie breaker on this?

[mholt]

I guess we technically could do func DateTime(d Date, t Time, referenceYear ...int) time.Time to make it optional.

But I think your point about "most significant unit" is a good one, and I like the parity with time.Date. Century, year, time. Or put another way: First two year digits, last 2 year digits and rest of date, time.

It's also probably best for this value to be explicitly set. Psychologically speaking, having it be the first argument may be a good way to encourage that.

I just switched it back.

[mholt]

Thank you both!!